The objective of this research is to investigate the amorphous semiconductor properties of the melanins and relate these properties to the preferential destruction of melanized tissues by environmental agents. This knowledge will then be used to develop testable hypotheses as to the etiology of various syndromes involving melanized tissues, and to develop controlled methods for the preferential killing of melanized tissues including human malignant melanoma. The effects of various drugs (e.g., chlorpromazine, Kanamycin, diethylamine) on the electronic properties of melanins, synthesized in vitro and isolated from melanoma cells, will be studied. Their effects on electrical conductivity and other amorphous semiconductor properties will be measured in vitro. This information will then be used as guidelines for experiments involving combined drug and physical agent (ultrasonics, ultraviolet, ionizing radiation) treatment of melanoma cells in culture and testing for survival. Experimentation will also be carried out using the platyfish-swordtail hybrid melanoma system to test the effect of these combined treatments in an animal system. The information gained from this investigation may then be used to design new treatments for human malignant melanoma.